Recent studies indicate that fecal transplants might have the potential to restore cognitive function in the elderly, allowing people to have a youthful mind much longer in life. Embedded in the lining of the gastrointestinal system, is the enteric nervous system (ENS). The ENS is responsible for controlling digestive functions and has been nicknamed the second brain, due to the over 500 million neurons found in the stomach. The communication system between the ENS and Central Nervous System (CNS) has been named the gut-brain axis. Recent studies have found that your brain affects your stomach, but more surprisingly, that the bacteria in your stomach may even affect your brain. The ENS can trigger mood shifts in people experiencing bowel issues. For example, people with Irritable Bowel Syndrome are more likely to suffer from anxiety and depression.
With more knowledge of what a healthy gut microbiome should look like and the negative impacts of low diversity in the gut microbiome, there has been an increase in diets and lifestyle changes that intend to improve bacteria diversity. These diets include cutting out gluten, and dairy products, among other foods and incorporating foods that introduce new beneficial bacteria. These lifestyle changes have proven to reduce the risk of inflammatory bowel disease, type 2 diabetes, cardiovascular disease, and cancer. When coupled with probiotics, microbiome diets have been proven to help with obesity, irritable bowel syndrome, and other gastrointestinal conditions.
Recent studies looked into further effects a healthy gut microbiome can have on human health and found that aging may be linked to age-related changes in our gut microbiome. The gut-brain axis may have an effect on cognitive function. For so long, we have thought aging to be inevitable, but what if we were able to take the knowledge we have on the gut-brain axis and cognitive function in order to revert the effects of aging? That is what scientists at the University of East Anglia and the University of Florence set out to do.
Dr. David Vauzour, with the University of East Anglia, was able to perform a fecal transplant from older mice to young adult mice. Fecal transplants involve the transplant of fecal matter from a healthy person to a patient in order to restore the microbiome in the gastrointestinal tract of the patient. Typically fecal transplants are used to treat C. difficile colitis, a bacterial infection that can cause diarrhea and inflammation of the colon, but this was used to test the effects fecal transplants can have on cognitive function. The young mice had a significant change to their microbiota and showed impaired spatial learning and memory. This was reflected by changes to cells in the hippocampus, which is responsible for learning and memory, along with other changes in neurotransmitters and synapses located in regions of the brain associated with aging. In summary, the young mice started acting like old mice in terms of cognitive function.
The study proves that age related shifts in the microbiome can alter aspects of the CNS. Although it is unknown at the moment whether transplants from young mice to older mice will be able to restore cognitive function, scientists remain hopeful that the new fad of manipulating microbiomes will be able to extend to improving cognitive function and quality of life of the elderly.